This invention lies in the area of fluid ejection type writing devices, and, more particularly, an improved fast response pulse actuated drive mechanism for use in an ink jet system or the like.
The prior art discloses a wide variety of non-impact type printing systems utilizing the principle of expelling or ejecting writing fluid from an orifice or a nozzle in a controlled fashion toward a medium, such as paper, where printing is to occur. The principle of continuous jet printers, and the means for controlling same, are well documented in the technical and patent literature. Another form of non-impact printer is the demand, or impulse printer, which generates a drop of controlled group of drops of ink or printing fluid only in response to electrical control signals representing the the alphanumerical data to be printed. As is well known, this type of demand system has the advantage of eliminating much of the control means required for deflecting the ink in the continuous type of system, and obviates a recirculation system for catching and reusing generated ink drops which are not directed toward the printing medium.
While the ink jet type printer has achieved a great deal of commercial success, and has contributed to narrowing the gap between the time of printing at the output and the time of calculation required by present day computer systems, there is a great need for faster response time printers. An approach to increasing the response time has been the construction of closely packed arrays of ink jets or orifices, which are pulsed in a controlled fashion. Other work has been done to reduce the size of the drop, smaller drops leading to the capability of higher response time and greater resolution in the resulting printing. Other examples of prior art systems devised to improve response time and/or resolution are techniques for modulation of the control impulses which actuate the printing transducer, and techniques for controlling the trajectory of the drop from the drop generator to the printing medium. However, in general a limiting factor in achieving a higher response time has been the basic problem of actuating and controlling the inertia of the drive elements, or transducers which control the frequency and size of the ink drops. There remains a substantial need for an arrangement which enables smaller drive elements which can respond with greater controlability and at higher speeds, for fast production of optimal size drops of printing fluid.